1. Field of the Invention
The present invention relates to power transmitting systems, and more particularly to systems conformed to modify ratio according to torque and speed.
2. Description of the Prior Art
Gearing of rotary power for maximum efficiency has had extensive use in the past, a typical powerplant having peaked power characteristics which are to be matched with a load. Similarly, transmission systems are deployed between a human and a driven article to match the optimal limb motion with the desired output rate. In each instance gear changes are typical and as more efficiency is desired a finer gear change increment is entailed. For this reason various infinite ratio gearing arrangements have been developed in the past which in one way or another modify ratio according to speed and torque. Some of these prior art systems utilized elliptic rollers through which the desired gearing is obtained, the rollers being shifted in the contact thereof against the driving and driven surfaces according to load. Systems of this kind though suitable for their purpose, entailed compound rolling surfaces with the attendant cost overhead and difficulty in assembly. Furthermore, systems utilizing such compound surfaces require various spring arrangements for loading the roller contact point to transmit torque. By virtue of the roller geometry and the eventual wear in the rolling surfaces relatively high loadings are required in order to load the contact area to the necessary level of frictional contact. Thus prior art systems of this kind lack the convenience of a small contact area, and in addition utilize spring elements indirectly with the attendant expense of added parts.